1. Field of the Invention
The present invention relates to a high pressure sealing apparatus, for example, a high pressure homogenizer for processing and segmentalizing material by dispersing, emulsifying or crushing the material included in a suspension liquid under high pressure, or for another example, a high-pressure pump for preventing excessive deformation of a packing member against a sliding rod or a sliding piston, and having good following ability and good sealing ability under high-pressure by closely contacting the rod or the piston with a proper contacting force, further, having good abrasion durability with a small degradation, and exerting high strength and high heat resisting property.
2. Description of the Related Art
Conventionally, for example, there is a packing assembly used for a machine such as a pump having a sliding plunger and a plunger bore receiving the plunger. This packing assembly is made by alternately stacking supple rings made of nitrile rubber and rigid rings made of fluorine resin having V-shaped sections interposed between upper and lower hard packing rings (for example, U.S. Pat. No. 5,577,737).
Further, there is another conventional packing assembly including: a packing gland nut threaded into a rear end of a plunger bore; a packing gland spacer abutting on the packing gland nut; a lubrication gland abutting on the packing gland spacer; a unitary stack of packing rings, each of which front face has a concave shape, and which rear face has a convex shape; a female adapter ring interposed between the lubrication gland and the packing rings, said female adapter ring of which concave front surface corresponding to the convex rear face of the packing rings abuts on the packing rings; and a male adapter ring positioned in front of the first packing ring in the stack, said male adapter ring of which convex rear face corresponding to the concave front face of the packing rings abuts on the packing rings (for example, U.S. Pat. No. 4,572,519).
However, the conventional packing assembly described in U.S. Pat. No. 5,577,737 slidably supports the plunger in the plunger bore by having a structure composed of alternately stacking supple rings made of nitrile rubber and rigid rings made of fluorine resin having V-shaped sections interposed between upper and lower hard packing rings. Therefore, when the plunger reciprocatingly slides under high-pressure, the supple ring is excessively resiliently deformed owing to its suppleness, and close contact ability to the plunger is increased. However, when an operating speed of the plunger or the rod is increased, or an inner pressure in the plunger bore is increased, or the plunger is heated, the suppleness and the strength of the supple ring is rapidly deteriorated, and the close contact ability and the sealing ability is reduced so that a leak is occurred.
Further, according to the conventional packing assembly described in U.S. Pat. No. 5,577,737, when the metallic plunger slides, abrasive resistance of the supple ring made of nitrile rubber is reduced, the supple ring is extremely worn and may crack, and a closely contacting position to the plunger is damaged by exceeding the stress limit. Resultingly, a mechanical life of the supple ring is short. Therefore, the supple ring should be frequently replaced with another supple ring. Considerable labor is required for maintenance check.
Thus, when the sealing ability is increased by increasing the suppleness of the supple ring against the metallic plunger to increase the contacting force, the supple ring lacks abrasion durability. Inversely, when the abrasion durability of the supple ring is increased, the suppleness of the supple ring is spoiled, and the sealing ability against the plunger is decreased. Therefore, conventionally, it is very difficult to attain the high-pressure seal having balanced sealing ability and abrasion durability. Basically, the conventional packing assembly described in U.S. Pat. No. 5,577,737 is used in a normal pressure of about 8000 to 12000 PSI and not used in a high pressure under 100 MPa.
Further, according to the conventional packing assembly described in U.S. Pat. No. 4,572,519, a plurality of separated packing rings having substantially V-shaped section are interposed between a female metallic adapter ring of which front face has a concave shape, and a male metallic adaptor ring of which rear face has a convex shape. Therefore, when the plunger reciprocatingly slides under high pressure, the rigidity of the male and female metallic adapter rings and lubricating ability of a lubrication gland are performed. However, similar to U.S. Pat. No. 5,577,737, the abrasion durability of the packing rings against the plunger is not sufficiently improved. Further, the packing ring lacks suppleness and flexibility, and may be deteriorated and cracked. Further, the contact point of the packing ring with the plunger may be damaged by exceeding the stress limit.
In the conventional packing assembly described in U.S. Pat. No. 4,572,519, the degradations of the abrasion durability, flexibility, resilient deformability, and strength of the packing ring are also occurred when the running speed of the plunger is increased, an inner pressure of the plunger bore is increased, or the temperature of the plunger is increased. Thus, the sealing ability of the packing assembly is not sufficient, a leak may occur, and a mechanical life time is short. The packing ring should be frequently replaced with another packing ring. Considerable labor is required for maintenance check.
Further, even in the conventional packing assembly described in U.S. Pat. No. 4,572,519, a plurality of separated packing rings having substantially V-shaped section are interposed between the female metallic adapter ring of which front face has the concave shape, and the male metallic adaptor ring of which rear face has the convex shape, as above described. Further, a packing gland threaded into an end of the plunger bore, a packing gland spacer fitting against the packing gland, and a lubrication ring abutting on the packing gland spacer are provided in the plunger bore. Therefore, the number of parts is large, and a structure of the packing assembly is complex. Therefore, producing and assembling the packing assembly are not easy, and considerable labor is required.
Accordingly, an object of at least certain implementations of the present invention is to provide a high pressure sealing apparatus having a good following ability by preventing excessive deformation of a packing member against a sliding rod or a sliding piston, a good sealing ability under high-pressure by closely contacting the rod or the piston with a proper contacting force, and a good abrasion durability with a small degradation, and exerting high strength having a long mechanical life time to ease maintenance check, and high heat resisting property, further, composed of the small number of parts, and having a simple structure to allow easy production and assembly.